Field of the Invention
Copper phthalocyanine pigments and iron hexacyanoferrate-III pigments, eg. Milori blue (C. I. Pigment Blue 27, C.I. No. 77510), have been used in conjunction to an increasing extent for pigmenting gravure printing inks and finishes, for which purpose the two pigments, because of their different dispersibilities, are milled separately in solvents or solvent mixtures or in binder solutions. Milori blue is difficult to disperse, and a particularly large amount of energy is therefore required to mill (disperse) this pigment.